A/N: I have no claim to owning MHA.
I am replying to things at the bottom and I also have a question pertaining to the story itself at the bottom as well as other things. Please check it because I like your guy's input. Part of my enjoyment of writing comes from you guys reading and saying things to me.
Five more years have passed. Izuku was now fifteen and it was just a few weeks until he could take the entrance exams to U.A., the hero school he had chosen to go to. He had gotten taller and had more muscle to him, still having a runner's build since he decided to build himself around speed due to Overhaul.
The only major change over the past five years to his wardrobe was that he actually got a custom plague mask to go along with the outfit he never changed over the past five years. The plague mask was not as long as Kai's and it had emerald green where Kai's had red and the gold was now silver instead. He also added claw like attachments to the sides of the mask that were reminiscent of Ryūko's dragon claw headpiece, the claws looking like fangs on his mask that he always had either on completely or around his neck. He would never go anywhere without it because it was one of his most prized possessions since it was inspired by the two people he looked up to the most. For the most part Izuku kept his wardrobe the same because it was a good look. He actually even considered making his casual outfit what he wore during hero work. He moves around in it just fine and with a quirk that lets you treat the area around you like play-doh gear isn't as necessary.
"Are you ready to try it?" Ryūko asked, them in the middle of training, with Kai nearby for tips. They were working on the one part of Overhaul Izuku waited to practice until he was confident completely in his ability. He had an easy time learning how to use Overhaul over the past five years, especially with tips and the teaching of Kai, who had mastered Overhaul when he had it.
It was a blow to the lab and the medical world when they found out that the man who had the "miracle touch" had lost his quirk. Kai stated it was a sickness he had so that it wouldn't be discovered he actually found a way to make quirks go from one person to another, feeling that there would be a good number of people who would abuse that knowledge. Project Overhaul was actually destroyed after Izuku got the quirk save for the knowledge of the ability to read the bridging layer of someone's blood. He was still an excellent doctor but nowhere near what he was with Overhaul. Izuku had offered to use Overhaul once he got comfortable healing others to heal them.
Despite the loss of Kai's Overhaul he still was a magnificent doctor and was actually working on a cure to a degenerative disease that affected people that had quirks that made them have metallic properties. He even had Izuku as a young assistant since the teen had Overhaul and the studies could go better with him there once in a while. Recovery Girl had actually offered Izuku an internship with her once he joins U.A., saying he had the perfect mettle to be a great doctor himself, even withholding overhaul as he had natural talent there.
The only part of Overhaul Izuku hadn't used yet was the fusion, or merging, ability. The ability to merge with another person and have both people's strengths, skills and most especially both people's quirks. It was something Kai only used enough to know how to do it, back then when he used it in the Yakuza finding most people filthy. Ryūko had offered to let Izuku try to merge with her.
"Just a minute." Kai reminded Izuku. "Overhaul was only mentally straining the first few times you used a section of it. Merging would definitely be a migraine at first so they had to pace it.
"Right." Izuku nodded as he put his hand over Ryūko's forearm. A sound of lightning was heard and smirk covered the two as the electric sound intensified. The smoke cleared and just one person was there. Izuku had done a perfect fusion. His hair had extended and gained blond streaks like Ryūko, and his eyes looked more reptilian. Izuku had gained height and muscle mass, both of their masses combining despite him not being as big as he should have with the total mass.
"Whoa." Izuku said as he rotated his arms and saw how his muscles looked much denser and compact. "This feels good."
"You have two systems of energy during fusions." Kai said. "Everything you both have is at your disposal. Try to use her quirk."
"Okay!" Izuku did a pose like he was trying to transform. "Wait how do I do that?"
"There should be a fire in your chest." Izuku suddenly heard Ryūko's voice in his head.
"Ah what the heck!?" The boy spun around trying to look for his mentor.
"You heard her on the first fusion?" His father figure asked. "That's amazing. Took me five fusions. Granted I didn't make a perfect fusion my first time."
"I can hear her!?"
"You did react."
"Picture it like you are the driver and she is a passenger." Kai explained. "She sees everything you see, feels everything you feel. You can't read each other's minds however. Person you fuse with can speak to you telepathically but you do have to speak verbally for them to hear you."
"That's weird and cool." Izuku stated. "So a fire in my chest?"
"Yep, try to picture it intensifying, like you are adding fuel to the fire."
"Alright!" Izuku felt the fire she was referring to and pictures the fire getting bigger. His body began to shift again but into a western like dragon. Soon looking close to Ryūko's dragon form but more like himself and slightly bigger. "Well this is cool!"
"You should split soon. It can give a headache the first few times." Kai reminded them.
"Okay." The large dragon like boy nodded before he reverted back to the normal fusion mode. After that another sound of crackling electricity erupted and smoke appeared around him. Seconds later it ended at Izuku and Ryūko was standing side by side.
"That was certainly an experience." The woman stated.
"How does it feel being the second person?" The Overhaul user was curious.
"Like I was floating there and also not." The woman explained. "It was odd."
"Is there a way that I can work alongside whoever I fuse with?" Izuku turned to his father figure.
The man actually raised an eyebrow. He had never considered that when he did use that aspect of Overhaul. "I never tried."
"That's what we should do!" The boy declared, his bubbly energy kicking in.
"You should give your head a rest for a minute." Ryūko stated.
"Alright." The boy nodded. "Plus I still have that paper to finish for the recommendation course."
"Make sure all of your assignments are done." Kai said. "Everything is due for your program at the end of the week." Kai was happy Izuku had gotten into a recommendation program, one actually sponsored by Ryūko. She had pushed for him to have one before he got Overhaul and they finally actually processed his papers once he got Overhaul, granted it was under the name manipulation, a fact that Ryūko didn't understand, but that was because she still didn't know the truth of Kai's past as a criminal.
Kai actually felt immense guilt not telling Ryūko the truth about his past. She was the closest person to him but she didn't know how evil he used to be. Part of him worried about how she didn't know because she was a new hero at the time he was the villain Overhaul but then again he was one of the more twisted villains that the Pro Hero society tried to cover up as best they could, like All For One.
"Got it!" The boy replied as he ran into the house.
"Where does he get that?" Ryūko laughed.
"Not me."
"You are too antisocial for that."
"It's not antisocial."
"Kai you talk to only me, Izuku, All Might and the people at your lab."
"Only people worth talking to."
"What about my friend Emi?" Ryūko asked. "Didn't you guys have that date yesterday?" Ryūko had recently decided to try and set Kai up with a friend of hers, the date was yesterday and he and Emi hadn't mentioned it yet. She didn't know what the feeling was but a feeling in her made her feel like she needed to know how that date went.
"It was okay." The man responded as they both entered Kai's house.
"Okay? Is that Kai for amazing?"
"It's Kai for okay." The man responded. "She is humorous but I don't feel that it would go anywhere."
"Did you at least let Emi down easily?" Ryūko didn't know why part of her felt happiness at the date not being a complete success.
"She was the first to state no interest in pursuing a relationship." The man replied.
"Really?"
"At the end she apologized and said that it was a plot to make someone jealous."
"She used you to make Aizawa jealous?" Ryūko wasn't surprised the Emi was still on Shota Aizawa, ever since those two met that woman would not stop trying to get the man's attention to no success.
"It was better than me saying there was no spark."
"A spark isn't instant." Ryūko said. "You wouldn't get one immediately sometimes."
"I got a spark of fatherhood when I met Izuku." Kai responded. While he had kept his time with the Yakuza a secret from the dragon hero who was his closest friend he had told her that Izuku was indeed adopted, while leaving out that Izuku was first found beaten half to death in an alley.
"Izuku is special." Ryūko agreed. The boy had grown on her so much in the years she had known him. He had an infectious energy of happiness every time he was around those two adults.
The two began to sit in silence while they enjoyed tea, something Kai was particularly good at making.
"I'm done!" A few minutes later Izuku came down the stairs.
"That fast?" Kai asked as the boy put his papers on the counter the two adults were at.
"It was easy." Izuku said.
"Izuku... You know this is college material?" Kai was holding a paper and looking at it.
"Yes?" Izuku responded.
"How much did you have left before this?" Kai asked.
"Just the last two."
"Hmm. This all looks correct." Kai nodded. It was a bit intimidating how intelligent Izuku was. The boy was just fifteen and could be smarter than Kai himself if given a year or two.
"How long am I supposed to keep Miss Tatsuma's quirk?" Izuku asked.
"What?" Both adults looked at him confused.
"I still feel it." Izuku answered their confusion.
"How?" Kai never had anyone's ability after he would separate from them. Did Overhaul somehow evolve when Izuku got it? "I have never felt someone's quirk after the fusion is over."
"Upgrade?" Ryūko asked. "Is it even possible for that?"
"While Overhaul was fused with a synthetic transfer quirk it was still the same Overhaul after." Kai wondered if he should call All Might and ask about if One For All ever evolved like this. Kai and All Might had become good friends over the years. At first All Might admitted it was him keeping watch on Kai because of his past but the two grew on each other as friends. All Might sometimes even trained Izuku because he said he found the boy's energy to be entertaining. It made Kai really happy that more and more people were coming around to realizing how much potential Izuku truly had.
"I'm going to try to use it." Izuku went back outside to have space for the dragon transformation.
The two adults followed in interest of Izuku's possible upgrade to Overhaul. Once outside Izuku stood in the middle of the modestly sized backyard and repeated the previous process of activating Ryūko's quirk, feeling the fire flare he actually did transform into a dragon like Ryūko's, except it looked solely like Izuku.
"Whoa!" The transformed teen moved his arms while studying the movement. "It feels a little different, a little weaker."
"It could be from the fact that we aren't in a fusion so you don't have the extra strength." The dragon hero thought out loud. "Or my dragon is stronger after being used more."
"Ah I feel weird." Izuku had a uncomfortable expression before he was forced out of his dragon form and back to normal. He no longer felt that fire in him, like the quirk was gone completely. "It's gone."
"You lost her quirk?" Kai asked.
"I can't feel it anymore."
"Maybe he can hold the quirks he gets in the fusions for a few minutes after the fusion has ended?" Ryūko offered.
"That adds an even bigger amount of variables to what you can do on the field." Kai stated.
"I don't really want to use the fusion without permission." Izuku stated.
"Permission?" Kai asked.
"That's combining myself with someone else and using both of our arsenals on my own. And now I can even use their quirks. It would seem wrong to do that without asking." Izuku explained.
Kai got a smile and patted his son on the head. "You are a good kid."
"I blame my upbringing." Izuku joked.
"Yea that's on me I guess." Kai nodded. "Want to go with me to visit my father?"
"Doesn't All Might want to train today?" The teen asked. He liked who counted as his grandfather now but he remembered All Might said he wanted to talk to him.
Kai remembered All Might saying he wanted to talk to Izuku about something important so he figured he should let the teen do that. "Alright. I'll be back in a few hours."
"I have to get back to the agency." Ryūko added, seeing this as a good time to go as well. "This nice girl who wants to intern with me and I am going to meet with her properly. Bye Izuku." She pat the boy on the shoulder as she and Kai walked out together.
"See you Izuku." Kai waved as he closed the door. He knew he could easily trust Izuku to be alright by himself at the house. They were in a good neighborhood and Izuku was more than capable of taking care of himself in any situation.
"Bye." The teen called out as he decided to go to his own secret Project. After he got Overhaul from Kai and learned that Kai had lost the quirk completely he decided to make his own Project Overhaul to find a way to duplicate Overhaul to give to Kai. He knew Kai was fine without the quirk but he also believed that the man should have it as well. He couldn't just pass it back because that would be spitting on Kai's original Project Overhaul, so he decided to learn how to perfectly copy the quirk to surprise Kai with.
The problem he had was finding a way to perfectly copy and it to give him. The transference quirk had lined itself into Overhaul in a slightly confusing manner, as well as how it webbed itself into Izuku's blood. The synthetic quirk acted as the layer Izuku wasn't born with, but Izuku didn't necessarily need to know it for this. Sure he had a copy of Kai's notes on the original Overhaul but he also needed a way to duplicate it to give Kai and like they have been finding out Izuku's Overhaul is slightly different, so he would have to account for that as well.
What Izuku needed was something that could copy his quirk from him so he can work on it without dealing with his own blood and the way everything had crossed over each other to confuse him. The synthetic quirk was indeed being the bridge between his blood and Overhaul, but instead of being a simple line between the two it was more like leaving three sets of wires together and finding them all tangled up. He knew he could do it but he really needed something that could untangle the three things so he could analyze the new Overhaul on its own and copy just it. Because at this point he wouldn't know if he would end up missing parts and writing in parts from his blood or the synthetic quirk instead.
Once he made that one all good and ready, and most likely in a vial, he could work on making a newer synthetic transfer quirk, but not one he would use to move the duplicate Overhaul. He would try to make it an inverse transfer, so it would be technically a synthetic receiving quirk.
That was a whole other bag of issues that Izuku wasn't going to stress about til he had the duplicate overhaul made. However he knew that he would have to make it a receiver of solely overhaul's coding so Kai wouldn't gain new quirks on accident every time he got different DNA near him. That was a risk especially since Kai was a doctor and spent a good portion of his time around DNA.
Izuku heard the front door open with the sound of keys. He closed the unmarked binder and slid it back onto the shelf by the counter as the arrival to the house spoke.
"Young Chisaki," It was All Might, who had gotten a key to the house a good two years before. Izuku actually saw All Might at least once a week and actually learned his real name a few months ago, it was Toshinori Yagi. "You are home correct?"
"In the dining room." Izuku answered. Truth was while it was meant to be a dining room they never really used it like that, only for get togethers. Most of the time they just ate at the kitchen counter. The dining room was mostly just a study or the room papers were done the most by the two men of the Chisaki name.
The large blond man of muscle came into the room with his signature large grin. "Hello Izuku. How have your studies been?"
"I'm finished with all of my assignments. They look good from what dad says. Between now and the recommendation exams I have no more assignments so I get to just train.
"That's excellent. I actually have something that has to do with your training."
"Is it that thing you mentioned on Saturday?"
"It is." Toshinori nodded. "While I am not in a position of extreme rush I want to ask if you'll be my successor."
Izuku waited to ask questions. He figured All Might had a different meaning than what Izuku thought.
Toshinori saw Izuku's patience and nodded to himself to continue. "We never mentioned it to you but the synthetic transfer quirk Kai made was actually copied from my quirk. It is a quirk that is two that had fused long ago at the dawn of the age of quirks, from the transfer quirk and a power stockpiling quirk. It was named One For All by the original holder. It is passed down from master to apprentice through time and each person holds the ideals of peace and being the one who will stand there to stop evil. I believe you are maybe one of the most perfect candidates for your generation to be the ninth holder of this quirk Izuku. Will you be that successor?"
Izuku thought for a second, not on his answer but the other information instead. His synthetic quirk was from this One For All? If Overhaul evolved from Kai to Izuku and All Might was the eighth holder of his quirk than changes definitely do happen with the quirks that get transferred. Izuku couldn't currently think of anyone that would make sense as the holder before All Might so it definitely got a glow up. He realized he should think on that later and give All Might his answer.
"I'm sorry Yagi sensei, but no."
Kai walked into the household of his father and was actually surprised to see a sad looking six year old girl. She had pale blue-gray hair long enough that it was almost reaching down to her waist. Her eyes carried a sad look and were bright red in color. Poking out from the right side of her forehead was a small, brown horn. She was staying near the farthest part of the couch in the living room from him and seemed scared by Kai's entrance to the house. Kai's pseudo father was also there.
"Hello father." Kai said his usual greeting.
"Ah hello Kai!" The old Yakuza boss stood up with a smile. "How have you been?"
"Well. Patient count in the hospital has lowered thankfully." The two would talk a bit about their different professions, Kai's moreso than Kenjiro's, his father.
"Regular villains have been less active as of late." Kenjiro nodded. "Plus they have you as a doctor. People can't get sick with you around."
Kai smiled from the praise before he asked a question that was growing. "May I ask who the girl is?"
Kenjiro lost his smile. "This is Eri. My granddaughter."
"Zenitsu and Seiran had a daughter?" Kai actually got an amused look for a second. He never really got along with Kenjiro's real child in Seiran, she was a bitch in Kai's opinion. He actually told Zenitsu last time he saw him like five years before that he thought Zenitsu deserved better in a woman. He rarely saw Zenitsu because the man did spend a lot of time traveling. Zenitsu saying he wanted to soak in the world's many stories.
"They did, but Seiran has disowned her." Kenjiro said the part that made him sad, he actually got into an argument with his daughter when she cast out Eri and he took he in.
"What!?" Kai looked back at the small child who had began to cry hearing about her mother disowning her. "Why would that..." He stopped himself before he cursed in front of a child. "Why would Zenitsu allow this!?"
"Can we talk about this in the other room?" Kenjiro really didn't want Eri to have to hear about the tragedy again. Kai nodded and they both went to the dining room.
"Father what happened?"
"Eri had an accident." Kenjiro started the story he had gotten from his daughter, but he would leave out the horrible things his daughter said. "She gained her quirk, it made Zenitsu... disappear completely."
"What?" Kai was straining to think what the quirk could be.
"Seiran heard a sound and a flash and when she came to the room Zenitsu was gone and his clothes had dropped to the ground like he had never been there. There was no trace of him and authorities had put out a search for him to no success, he is just gone. Seiran believed she vaporized her own father on purpose and called Eri a witch, and more things that hurt Eri. She hasn't properly opened up since she was left here."
"Seiran just left her here on your doorstep?" Kai asked.
"She more or less kicked Eri out of the apartment they live in and I was thankfully coming over to visit yesterday when this happened." The Yakuza boss was grateful to the Lord that he had been there. Who knows what would have happened to the poor child if he wasn't there.
"Please tell me you confronted Seiran about this?" Kai properly would have committed assault if he were there. How could that stupid woman think Eri would do such a thing to her own father on purpose?
"We had it out, and I disowned her." Kenjiro was upset he disowned his own blood but what she said was unforgivable.
"You're a better person than me." Kai breathed out. "I would have done something bad."
"You can't erase evidence anymore since you gave Izuku Overhaul." Kenjiro had been told what happened with the quirk and he was actually proud of Kai for doing that with the thinking his son had.
"I would have found a way." Kai stated. He looked towards the other room where he could see Eri was still huddled in the corner of the couch crying. He couldn't believe Seiran was this much of a bitch. He had a low bar for the woman but fuck did she show it wasn't properly set low enough. The only person lower to him on a scale of shitty parents was Izuku's real father.
"Eri will be staying with you?"
"I believe so." Kenjiro nodded. "I might be too old to raise another kid but I will gladly do it again."
Kai had his gut tell him something again. It was the same guiding idea he had when meeting Izuku. "I'll raise her."
"You will?" Kenjiro raised an eyebrow.
"You did say yourself that you are up there in age. I am raising Izuku just fine and I... have that feeling again."
Kenjiro smiled proudly. Kai was really a great person in his eyes. "You plan on just adopting every child who needs a home in Musutafu aren't you?"
"If they need a home I have a home." Kai nodded. "That house has four rooms and only two are in use with just me and Izuku there."
"You are a good person Kai " Kenjiro put a hand on his son's shoulder. "I have never been prouder as a father."
Kai smiled. "Thank you. I think I should introduce myself to Eri now."
"That will help. She hasn't opened up easily since the event yesterday."
The two adults returned to the living room where Eri was.
"Hi Eri." Kai crouched to eye level with the small girl. "I'm Kai."
"He-hello." The girl was worried he would be like her mother.
"Your horn looks nice." Kai decided to just go with small talk to show he meant no harm. "I actually know a co-worker who has three of them."
"Three?" The girl asked.
"Yea. They are curly and go right across his forehead." Kai traced where they were.
"Are... they also... cursed?"
"I don't believe anyone is cursed." Kai said. Did her mother make Eri believe she was a curse? Just like Izuku's father made him think he was worthless?
"She sai-d that I am... cursed." Eri was crying.
"She's wrong. If anything she is a curse." Kai wished he had Overhaul for just a second to make Seiran blow up.
"B-ut she said-"
"She's wrong. I am a professional doctor who studies people down to their DNA. According to everything I have ever studied all I see is a little girl who is far from ever being a curse."
"What is DNA?"
"It's what makes us what we are. I can even prove it to you that you are not a curse if you'd like?"
"How?" Eri had a bit of hope but it was followed by a lot of doubt.
"I have a lab where I can show you exactly that you aren't a curse. It helps people."
The little girl was quiet for a second. "Can... we go there?"
Kai smiled. "We sure can."
All Might blinked while looking at Izuku. He was surprised that Izuku turned him down. Well honestly for all of a second because he was only eighty percent sure Izuku would say yes.
"You say no Izuku?"
"Sorry." Izuku apologized. "It's just... Dad was the first person to believe in me. He gave me Overhaul, his own quirk! He gave it up for me because he thought I had so much potential that to take another quirk feels like... it feels like-"
"Like you would be spitting on Kai's actions." Toshinori couldn't blame Izuku at all for that reasoning. He did feel that Izuku would say no because of Overhaul, he really only offered to see if Izuku would take it.
"I want to honor dad's actions and his quirk. If I take One For All I can't do that as well."
Toshinori gave a smile and oat Izuku's shoulder. "I understand completely Izuku. I actually thought you would say something like that which is why I had this second thing in mind. Even though I am in no risk right now an event five years ago made me realize I should be more responsible of my actions and with One For All. I do still need a successor and I want to recruit you as a finder slash advisor of sorts. I know your goals to reshape the hero system and fix the corruption, that is accounted for. It is okay if you find someone who might not fit my exact mold of a hero but yours instead."
"Our ideas kind of overlap." Izuku pointed out. "It would just be someone who wants to be a hero for the sake of helping others foremost, not wanting fame or popularity as their main reason."
"I agree with that completely." The Pro Hero nodded. "You are a smart lad. I know you will find someone worthy of One For All." He then remembered something he meant to say. "Before I forget to mention it. I am taking a job at U.A. this year."
"You are?"
"Admittedly it is mostly to find a new successor." Toshinori chuckled and rubbed the back of his head. "I might still be at the top of my game but I should have an apprentice to pass on my skills and One For All to regardless. Life does have many unexpected things at play so I shouldn't be reckless."
"What will you be teaching?"
"The Foundational Heroics Studies class. The previous teacher has decided to retire to stave off his growing health issues and age. This is honestly a good opportunity because I believe that the current generations best should train all of the next generation because you should all surpass us."
Izuku nodded, he understood the points but changed the subject to a question he had. "Does One For All evolve with each holder?"
"Hmm?" The man raised an eyebrow. "Does it evolve?"
"It would explain Overhaul's evolution."
"Overhaul has evolved?"
"As far as I know it is just the ability to keep quirks for a short time after I am in a fusion with them."
"That is an interesting evolution." The man was trying to think on any way One For All has evolved from what he knew. "The power stockpiling does make One For All gain more power as it is passed from person to person. I have not noticed anything else in my knowledge but it is possible I am just not using it in a way that would show any other evolution."
"This makes me wonder what else changed about Overhaul."
"This is indeed a curious subject. Does Kai know about this already?"
"Dad knows. I went to him first about it, I was unaware of the quirks presence after a separate being a new thing."
"I am actually curious about any differences in One For All now to be honest." The thought has not left Toshinori's head since it was put there. "I apologize for my quick departure but I am going to speak with a friend of my sensei's, he might be able to tell me how it has changed from her to me." He got up.
"That's okay. I still have stuff to do here."
"Take care Young Chisaki." The blond hero pat Izuku on the head before he left.
Kai would admit he did have a motive past helping Eri believe she wasn't a curse or anything close to that. It was a good motive, he could identify her quirk easily at his lab since one of the things they did at the lab was the beginnings of his Project Overhaul where he learned about the bridge layer of blood that was one of the most effective way of identifying quirks in people.
"This will only pinch for a second." Kai said reassuringly to Eri while he held the syringe, she nodded and he put it into her arm, drawing out the necessary amount of blood for this.
"See? Just a pinch." The man was glad Eri had gotten calmer around him in the short time she knew him.
"How does it show things?" The little girl asked.
"With this." Kai finished wiping off her arm and wheeled his chair behind him to machine. "This helps us see the building blocks of blood at a level our eyes cannot. It will let us see far enough down that I can show you that there is nothing in your blood that makes you cursed."
"Okay." Eri was paying hard attention, absorbing everything Kai said because he was so kind with how he spoke.
The original holder of Overhaul began to use the machine and inspected the blood, making sure to show what was on his small screen on another screen that Eri could see. From just a first glance he easily identified what class of quirk Eri had.
There were emitter type quirks, abilities that allow the user to generate and possibly control certain things, or alter existing things around them in certain ways. Good examples were like the ability to control or generate fire, water, it any of the elements. This was the most common type of quirk.
There were transformation type quirks, abilities that cause the user to take on a temporary alteration of some kind. Sometimes enhancing existing features, removing features, or adding new features to the body altogether. A good example was a person Kai was currently helping with a deteriorative disease from his quirk, that let his skin turn to bronze.
There were also mutant quirks, abilities that cause the user a permanent "abnormality" directly related to their power. Mutant-type Quirks create bodily structures that grant the user more complex abilities that Emitter and Transformation Quirks cannot safely provide. They could be used in a similar manner to Emitter-type Quirks. Good examples were people who had wings, extra arms, a child he actually helped with a sickness back when he had Overhaul who's head had the resemblance of a glue-dispenser.
Those were the three classes if quirks but there was also a sub class that was known as accumulation-type quirks. Powers that, in order to function properly, require the user accumulate something ahead of time, such as power, energy, mass, or a particular resource. All Might's One For All was an accumulation-type quirk and he identified Eri's as another one. Looking at it he saw parts that were actually pretty unique to what he has seen before, but to be fair accumulation quirks all were pretty unique. They had more to that bridge layer and the quirk itself to store whatever energy they gather to be used in the quirk. One thing that couldn't be found though was whatever Eri used as an energy source for her power, it all must have been used the day prior on her father.
"See this?" Kai turned so he could face the six year old girl. He was indicating to the bridge layer and the quirk she had. "This is your power right here. It doesn't have any part that indicates it as being a curse, it is just a blank power that will only be a curse if you yourself want to make it one."
"I don't want it to be a curse."
"Then it is not a curse." He stated, liking how that made Eri replace some of her fear and worry with happiness. "We can even study it to find out how to use it for something better."
"Like what?"
"Right now I don't know exactly, this is new to me. But would you like to find out what it is?" Eri nodded in response. "That's good. I don't want to do this if it makes you uncomfortable."
"What does that do?" Eri pointed at the screen at the part of her blood that was her quirk.
"That part specifically is your quirk. It stores energy from what I can see but I currently don't know what type it stores. What you do with the energy is also a mystery."
"It made dad leave." Eri was getting sad again.
"I am sure he is fine wherever he is and he doesn't blame you. Zenitsu is a good person."
"You knew dad?" Eri was confused because she had never seen Kai before today.
"I haven't seen him in years, but I used to know him well."
The door opened and Izuku walked into the lab, before the teen looked confused to see Kai and Eri.
"Dad?"
"Izuku?"
"What are you doing here?" Both guys asked at the same time. "Wait I asked first." They continued to speak at the same time.
"Izuku this is my lab so I think I get an answer first." Kai was wondering why his son was here, and why he had a black binder with him.
Damn. Izuku didn't think his dad would be at the lab. He wanted to try to work on his project more. "I was umm... working?"
"On what?"
"Project Overhaul."
"Project Overhaul ended five years ago Izuku."
"What's Project Overhaul?" Eri got confused. She wasn't as uncomfortable around Izuku because he was Kai's son, and she liked Kai. She also found that odd mask currently around Izuku's neck odd. It looked like the one Kai had dangling around his own neck.
"It was a project to pass on something of mine to Izuku." Kai explained. "Izuku this is Eri. Eri this is Izuku. You two are siblings now."
"Really?" Izuku asked, not in a negative way at all, but one of surprise.
"Yes. Eri will be joining our house."
"You... want me to stay with you?" Eri asked.
"If you want to." Kai wanted her to feel like it was her choice.
"But I am a... curse."
"No you aren't." Kai shook his head. "One person giving out a poor judgement of you does not make you that thing."
Izuku spoke, feeling the urge to help the little girl also. "My original dad called me worthless, he was wrong "
Eri looked at Izuku, he didn't seem worthless so why would anyone say that? "Original dad?"
"Not him " Izuku didn't want her to think negatively of Kai. "But this one jerk. He thought I was worthless and abandoned me. Kai found me and took me in because he saw what I really was."
"What was that?" Eri asked.
"The same as you." Kai poked Eri's shoulder while having a reassuring smile, something he had mastered while being Izuku's surrogate father. "Full of good potential."
Eri gained a smile of her own. "I have potential?"
"Dad doesn't lie." Izuku stated.
"I try not to." He suddenly remembered the lie that was him not telling Ryūko of his past. Izuku was a child and knew but of it, why couldn't he just tell her, an adult who over time he had gained a trusting friendship with? He shook that thought from his head and went back to the issue of Izuku's binder. "Izuku why are you working on Project Overhaul?"
"Because I wanted to duplicate Overhaul so you can have at least a copy of it."
Kai gained a grin. Of course Izuku would try to do something like that. "How far have you gotten?"
"I managed to get the script of my Overhaul down but since I can't just give you the original I have to find a way to make a copy in new blood without just passing it on to someone."
Kai was actually invested in this idea now. Not because he missed Overhaul, but mostly because he enjoyed seeing Izuku at work on a project. The kid was too smart and this was a good test for him. "Have you tried seeing if a sample of the quirkless blood we have here can house it?"
"I tried but whatever happened when it got in my blood made it and the transfer quirk not want to do that. It's like after it was transferred into me the quirks don't want to be in anything else but my own blood."
Kai nodded. "That would make sense if it is like the original transfer quirk, which Toshinori states can't be taken unwillingly. You don't want to pass on Overhaul to this blood sample so it could be assumed that no matter what you can't plant the coding from your own blood."
"I guess that is true. I think I just overlooked that part. If anything I would have to write Overhaul from complete scratch on a reverse version of the transfer quirk."
"A retrieving quirk." Kai remarked. He had to admit that the plan sounded good but he still wanted to check if Izuku checked his own work. "What about if different blood with different quirks come into contact with this retrieving quirk?"
"I can write it down in a way that the only compatible quirk it can take is Overhaul. The retrieval quirk can be the bridge layer again if you don't have yours anymore and I can work both sides of it to only mix with your blood."
The original owner of Overhaul had a grin of pride, his son had covered his bases. "Well now that I know about your project that means we can continue it together."
Izuku gained his own large smile. "Great! I saw Mister Yagi earlier."
"Why do you have bird beaks?" Eri spoke for the first time in a little bit, wanting to know about Kai and Izuku's masks.
"I used to have it as a symbol of one goal I had but after that it became a goal with a different meaning." Kai answered. "Cure the world, one of my goals as a doctor."
"Mine is kinda based on my two heroes." Izuku admitted.
"Oh." Eri nodded in understanding. "Who is Overhaul?"
"It is my quirk." Izuku answered. "I can manipulate anything I touch." He showed the girl what Overhaul could do by manipulating the chair next to him in a perfect ball of wood before shifting it back to normal.
"Wow that is cool!" Eri had wide eyes. "What is yours Mister Kai?"
"Overhaul. I gave it to Izuku because I thought he would do better with it."
"But I thought he said he was going to give you it?" Eri got confused.
"I want to copy it and make a second one so dad can have one of them."
"But I thought quirks were unique?" At least Eri's dad told her that.
"They are, but we are smart." Izuku replied, not having arrogance in that statement like one normally would. "What is yours Eri?"
Eri got a worried look for all of a second, afraid that Izuku would call her a curse before that thought left her head because it didn't make sense to her that he would. "I don't know."
"It is an accumulation type quirk." Kai stated. "Just a little more research or even a test might show what she can do with it."
Izuku sat down in the chair he had previously manipulated, eager to help Eri because he had quickly taken a liking to the horned girl. "What is the energy she uses?"
"That is currently unknown. But from a small look at this section of the blood makes me think it isn't regular energy." The man zoomed in on a section of Eri's quirk on the screen. "It seems closer to perhaps... radiation?"
"Maybe the energy is a compound?" The current holder of Overhaul offered. "There is always a small layer of radiation in the air and she might take that in as well as something else that isn't currently there yet."
Kai nodded and began to type away at his computer. If it were a compound maybe they could find it in her as long as they search for the compound that had the radiation.
"What type of radiation is it?" Izuku had already grabbed a new binder, a tradition of both of the Chisaki men that no matter what it is, a study gets a binder.
After a bit of enhancing the DNA to get deeper into it he found radiation in a compound, only seen within her quirk. "Sunlight."
"That is interesting." The masked teen nodded and began to jot down notes, making a section labeled energy. "Light radiation makes whatever her quirk is be more helpful or at least build up more in the daytime."
"What does my quirk do?" Eri was entranced by how efficient Kai and Izuku were at this. They just kept bouncing things off of eachother and it made them go that much faster.
"We can test it." Izuku offered. "What does her quirk do from what we know?"
"The one time it was used resulted in Zenitsu disappearing." Kai said in a quieter tone to Izuku.
The teen nodded, understanding the reason for the quiet tone. "Maybe she releases the energy onto living organisms for an affect of teleportation?"
"Possibly. We can test it on a plant since that doesn't have as much risk. Eri will you be fine with that?"
The horned girl nodded. "I can do it."
Kai nodded. "I shall go get one from the other room."
Eri looked at Izuku once they were left in the room. "Did your dad really call you worthless?"
"My original father did." The teen nodded. "Dad here made me realize that my original father was a jerk and helped me get better."
"Mom said I was a curse." Eri replied.
"Well she was wrong. I haven't seen you do anything curse like since I got here. Based on evidence you would be actually the opposite."
"Really?"
"Yep." Izuku nodded. "If dad says so then definitely. He hasn't been wrong about people since I met him."
Kai came back with a plant, a pot with four blue and orange flowers in it. "Eri do you remember what it felt like when you released your energy the first time?"
"Yes." She felt happy right before it happened.
"Try to make that feeling again but touch just one of these flowers while doing it."
"Okay." Eri nodded and tried to make herself happy while touching the plant. At first she couldn't think of a positive thing because her thoughts went to her parents, one who was now gone and the other hated her. However she got better memories when she just thought if the past but of time that day with Kai and Izuku, both of whom accepted her and were really nice. Her horn began to give off light and her hand glowed before the plant had the same pale yellow, white light and a flash encompassed it.
When everyone could see again Kai noticed first that the flower wasn't gone, it had... shrank? No it actually looked like it aged rapidly in reverse. He then noticed Eri's horn had gotten shorter.
"I think I know what it does!" Izuku announced.
"I think I have an idea too." Kai nodded. "State yours first Izuku."
"The plant didn't teleport like I originally thought, it aged backwards at a really fast pace. Her horn seems to be where the energy is stored primarily too. If I had to say I think that she doesn't make things age in reverse, but actually... rewinds it."
"I had the same idea." Kai nodded. "Eri would you like to continue testing on the flowers?"
"Uh-huh." Eri nodded, she was amazed by what just happened.
"Any of the other flowers will work. One at a time please."
"Okay." The girl put her hand on another flower and tried again, her horn gave off a slightly smaller glow and the flower flashed again. When it came back into vision it had indeed gone back a stage in the flowers life, losing its blue rim. However it wasn't as far back in its life cycle as the other. Eri's horn had shortened again, now looking like a stub of a horn. "Was that good?" Eri asked.
"It was perfect." Kai nodded. "The amount of energy changes how much it ages backwards."
"Her horn shows how much she has. If I had to assume since the horn is now flat she might have little to no energy left." Izuku stated.
"Eri can you feel any energy in your horn?"
The girl tried to feel her horn, by actually touching it at first. "I can't feel it."
"Try feeling it with your mind." Kai offered.
She tried to think about the horn and then felt a light in her mind, a pale yellow, white light just like when she used the energy. "I can feel it!" She announced happily.
Both guys had smiles. "Excellent, how much do you have?"
"Umm... not that much." Eri stated.
"So the horn does grow with the energy you have." Kai nodded. "I think we should call this quirk Rewind, since that is what it does. Do you like that Eri?"
"I like it." She nodded.
Later on the three had returned to the Chisaki household and Eri was given a room right next to Izuku's. She loved the room and how it had a view of the decently sized backyard.
Izuku and Kai were at the dining table while Eri was looking around the first floor of the house.
"So if she rewinds things does that mean that Mister Zenitsu got rewinded so far back he got to a point where he never existed?" Izuku asked.
"As sad as that seems it is the best explanation." Kai nodded, making sure to watch Eri while she was looking at things in the kitchen. "Accumulation quirks build up energy from the second a person is born but they don't gain the ability to release that energy until around four or five. When it released for the first time and she did it to Zenitsu he got hit with all of it. I don't think there is any way short of time travel, which is a big impossibility at this point unless a quirk is gained that does that, to get Zenitsu back."
Izuku frowned at that. He didn't like that Eri would have to go on with the knowledge that she accidentally killed her own father.
Kai knew what his son was thinking. "It was an accident and we have to make sure she knows that. Until she gets better control I think it would be wise if she didn't really have physical contact with anyone."
Izuku got an idea. "Overhaul! She can train with me!"
"How so?"
"It seems like she might be able too not as much de-age things as make them go to a previous state. I can use Overhaul to manipulate myself to something simple, like an extra finger or so on, and she can train by reverting me to normal."
"That does sound like a good idea, but it hinges on your idea that she rewinds things to a previous state and not just de-age them."
The teen lit up again. "I know how to prove it!" He ran outside, leaving Kai the wonder what his son was thinking.
Izuku ran back in with a flower, right to Eri. "Eri try to rewind this flower as little as you can."
"Okay." Eri touched it, but before she activated her quirk she saw Izuku rip a few petals off of the flower.
"Still do it." Izuku said when he saw he confused look. The horned girl nodded and her quirk soon activated. After the flash the flower didn't look like it got any younger but it had all of its petals like Izuku hadn't torn them off.
"Well I guess it is not just de-aging." Kai stated.
"So she can train it with me?" Izuku asked.
"If it has no negative consequences then I'll allow it." Kai nodded.
It was now late evening and Ryūko stopped by, something she did a lot since she really liked Kai's and Izuku's company. The dragon hero was surprised to see a new addition to the household in Eri but took a quick liking to the girl, just like she did with Izuku. Eri also took a liking to Ryūko and liked her dragon claws mask.
A bit later Izuku and Eri were having fun while training, meaning Izuku kept adding extra joints to the fingers on his one hand and Eri was laughing while tapping it back to normal because it was really a game of them clapping each other's and their own hands in a pattern. Ryūko and Kai were at their usual spot of the dining room table with cups of tea.
"So how many kids are you going to adopt?" Ryūko asked. She had been told about how Eri was cast out by her real mother and that made the dragon woman instantly hate Eri's mother.
"Well I do have one more room left." Kai had a grin.
"So you are going to adopt another kid?"
"If I come across a third kid who's original parents didn't accept them then I have the room for them." Kai said this not knowing that in a few short weeks that room would actually be occupied.
"You'd make a good biological father." Ryūko said.
"This is just as good." Kai sipped his tea. "It does bother me that my oldest kid is almost as smart as me and isn't in high school yet."
"Give him a few months or a year at most."
"I don't doubt that." Kai then thought to return Ryūko's compliment. "You'd be a good mother."
The blond got a sad look for a second and Kai felt like he fucked up. "I wish I could be a mother."
"You can't be one?"
"I can't, not even through a donor or anything." She hadn't told anyone when she found out a few months prior because it was so upsetting to her. She loved kids and always thought she would be a good mother, but finding out she couldn't have her own kids just... hurt.
Kai frowned, before he shook his head. "Whether you can have a biological kid or not shouldn't matter. You're a good mother to Izuku at least."
"He thinks of me as a mother?" Ryūko sounded shocked but also hopeful.
"Positive female role model in his life. Plus I heard him refer to you as mom one time." Kai said hoping it would make the blonde across from him feel better.
It did because she smiled as she looked into the other room where Izuku was still playing with Eri. Maybe she had been a mother for a while without realizing it. She was thankful for Kai and Izuku now more than ever.
A few weeks later
Izuku was bouncing on his feet waiting by his front door. It was the day of his exams and he was excited as an understatement. The exams allowed for whichever hero sponsoring the test takers to accompany them, and Ryūko was on her own way to U.A. but he was waiting for his dad and new little sister to get ready. They were his ride to the exams.
Eri had done something close to Izuku and mimicked Ryūko and Kai's style a bit. She had a red dress shirt with a frilled collar and a plain green pinafore with two large, golden buttons on either side of her chest. Under this, she wears gray tights and a large set of tan boots. After convincing Kai she even got her own plague doctor mask like his and Izuku but she was told to not wear it all the time because he didn't want her to accidentally forget to breath with it on, especially since she had become easily excitable since joining the Chisaki household, one time talking for a good while without taking a single breath. Hers had a darker red but still kept the same gold trimming. She had also copied after Izuku in never leaving home without it, she wouldn't even leave a room without it. Eri had taken to being a Chisaki really well, loving her new father and older brother.
At one point she accidentally called Ryūko mom to get her attention and Ryūko got really happy about it, saying that Eri can do that whenever she wants. Then Izuku admitted to Ryūko about his once saying that and it made Ryūko even happier. Izuku had honestly always felt like Ryūko was the closest thing he would have to a mom and was glad he told her that.
That whole situation made Izuku decide to do something that would benefit him, Eri, Ryūko and Kai, especially the two adults. Get Ryūko and Kai to realize they like each other. He knew they did but was surprised that they didn't, especially when one of them was a brilliant scientist and the other was intelligent in her own right. He thought that the whole having two kids call them both mom and dad would make them wonder if they like each other but it didn't, it the two just really didn't know how to do anything about it, which he thought was dumb. Like they knew each other for ten years, even basically raising a kid together, and the thought never crossed their minds? Maybe it did but they didn't mention it because they didn't want to jeopardize their current situation and especially how they were raising Izuku, but he wanted them to just realize they liked each other.
Kai and Izuku had managed to make the reverse transfer quirk, the retrieval quirk, but had no success at all when it came to Overhaul. Even trying to go farther into the quirk to write its coding from scratch on a blank slate proved futile as the quirk had changed with Izuku and made itself too confusing and complex, especially since it had twisted itself with Izuku's blood and his synthetic transfer quirk, unraveling them even in a separate drop was too difficult to do so they wouldn't know what they were writing down.
Izuku was grinning as Kai finally came around the corner with Eri, who's horn had gotten longer, about five centimeters longer.
"Ready to go Izuku?" Kai didn't know why he asked when the teen was visibly vibrating trying to stay still.
"I'm ready!" Izuku said louder than he meant to.
His father laughed. "Well let's get you to your test."
"Yea!" Izuku barreled out the door, ready to finally show all of his potential.
A/N: This is the end of chapter two. It's shorter I l ow but I wanted to get a few things established and the entrance exams should get it's own chapter as to not overshadow anything else, especially when a few things of interest happened this chapter.
I read some reviews and did think should I have just split Overhaul? But that wasn't possible at that point since like, it's a complete transfer. All Might lost One For All to Izuku in cannon completely but it took a while because it was a lot to transfer. However this feels like a reasonable way to give Kai Overhaul back as a duplicate, which will take a minute because they do need one more person to help them actually be able to do it.
Hope I brought Eri into the story in a way people liked. I was actually wondering if anyone caught onto Zenitsu being her dad in chapter one when it was stated that he was Kenjiro's son-in-law.
I will actually give a shout-out to whoever can guess the fourth member of the Chisaki household I foreshadowed, I didn't give hints but just look at Izuku's and Eri's pasts and you can find them because parallels.
THIS PART IS KINDA IMPORTANT but also a spoiler I guess. I had an idea for U.A., since I like making things different in each story I write. I thought to myself Kai would be a cool teacher too. And then thought what's stopping me from having that happen? I actually have a plan for four different hero course classes, the forty split into ten (all placements decided already if I go this route) and was wondering how people would react to that. Lemme know.
Also I hope the All Might situations make sense this story. I want him to still be the hero course teacher so I made him think damn I almost died without a successor and decide to at least have one lined up. I don't know who it is myself personally, which is funny because my two thoughts are Mirio and somehow Eri.
Imma now do that thing where I reply to you guys.
FalconPuncher: That's funny to me since this was built off of a thought from The Heroic Saint and me thinking what if Kai did save Izuku? Without all of the Saints Row stuff.
The Royal Mage: I thought it was odd no one else used Overhaul in as many fanfics. The Hero boards are decided using approval ratings and a hero's percentage of crime control and such.
Mem0ry: I admit some of my paragraphs are way too long. I always try to keep all of a certain thing in one paragraph but I plan on working on it, writers shouldn't ignore reviews when they help their writing skill. Glad you like the story and I hope my improvement makes it easier to read.
Yamajiji: Oh Yea. I definitely plan on making Kai and Ryūko a ship here. I like the whole brought together family going on here. Glad you like it my guy, as well as my other stories. I like when you guys reference the other works I have.
Im The Person: I hope this is quick enough for you. If it is someone unique for OFA that will probably make it be decided as the story goes, or until enough people make a good case for an exact person to get it. Izuku actually had a pretty interesting time at the exams and such. Although I don't think he would be as much of a major show off. The pairing is definitely unique because when I checked how many other fics have it in their tags there was less than twenty. And I definitely don't write Harems, not my style at all, I'm a monogamous relationship type of person. He will definitely expose Hisashi, that all had a whole arc around it because oh do I make that something.
BlazingCharizard01: Don't worry, Kai is still killing it as a doctor.
maxharbour3: Lol I do kinda write long chapters. Glad you liked it.
kasimrox3009: Glad you liked the long chapter. I thought it might have been a bit much but you all seemed to love it, you all even seem to like Kai x Ryūko in this. I figured I would let you guys decide who gets it but I kinda like this Izuku having just Overhaul, in my stories I feel like One For All would overshadow any of the unique powers and such Izuku is given.
Jaacra: I take it you like Clear Blooded? Nice.
NyaNyaKittyFace: Kai losing Overhaul was a hit, but he is Kai Chisaki, he is too smart to be kept down. Plus I have made a Project Overhaul 2.0 because of course Izuku would want Kai to have it as well. Izuku's Overhaul did evolve, as stated, but I haven't explored all of the evolutions to it yet but I think I know the other thing I might add to it, which should make sense for Overhaul. Sorry I gotta say no to Izumomo, I'm a fan of that ship but I try to give each story a different main pairing. You will hopefully like it here. If you want a story of mine with Izumomo I offer The Heroic Saint. It has a rough first chapter since that was my actual start writing but in my opinion but it gets better as it goes. I also understand the All Might thing but here his fight still jarred him as a damn I should have a successor moment. I also completely understand your reasoning to Mirio, that is a good point. Dude your whole last paragraph, ugh I want to say stuff about every point but damn I don't wanna spoil.
Toby860: I explain it hopefully good enough as blood is really complicated in this story and even Overhaul would struggle to build blood the proper way.
PEJP BengtZone V2: Hisashi has no idea Izuku lived thankfully. I don't write things like what you said about Hisashi and Ryūko, I just... no. I wouldn't be comfortable writing that, which is kinda weird considering chapter one of my story Clear Blooded has some dark stuff, but not that stuff. Plus Ryūko can't have kids in any way here. It'll be a bit before he exposed his father I believe. I don't actually think Kai made trigger here, at least not yet. I don't even think Kai would be the one to make it here. He has no trace of Overhaul in him right now anyways since the transfer to Izuku made him lose it completely. As for the ghost visions, he has a synthetic transfer quirk, not the real One For All, so I don't think he would, if anything he would get some of Kai but Kai is alive so he can't get ghost visions of him as far as I know.
Hope you liked this chapter, I always worry that I make a chapter worse than the one before it and you all loved chapter one so much I am worried I didn't meet expectations. Let me know how it is regardless and have a good day!